Sophisticated start. You could go with black and white photography, architectural pieces, art pieces- anything you love on the wall. Then, add pillows in the colors of the art work. If you want to stay more monochromatic, think in terms of textural interest, such as a shag area rug, pillows with seam detailing, etc.

Where is your house? Low maintenance plants depend on the zone. I wouldn't plant in your rock skirt. Ideally you'd put your rock skirt around the house and then planting beds outside of that. The skirt keeps mud and dirt off the house and let's you spray for bugs etc. since your skirt runs right up to the driveway on that side, I think your options for plants would be some large pots or window boxes. I'd paint your foundation the same color as your grout in the brick to help it blend in.

What colour scheme did you end up picking?

Without knowing any more info , I'd say its near impossible for anyone but you to know what colour/s to choose -- do you want the house to blend in but have its own style , or do you want it to stand out ? What colours are your main furniture items and even kitchen etc ? For xxample , if keeping the beige walls , how about doing the eves and gutters and garage door in a tangy ( bright , but not glaring ) orange -- this would work with the existing colours and not require a complete repaint . BUT if your kitchen was mainly various shades of , say , green and teal , and your lounge suite and duvet covers were mainly blue hues , that may 'feel' funny , clashing with the exterior ? Of course , blue and beige exterior may not work with the brown aluminium , as youve recognised . Another option ( a bit hard to tell from the pictures ) is that a light grey ( repaint the beige ) with mid-charcoal base boards may work with the brown aluminium , then a bright colour on the gutters and front and rear doors to suit -- anything from sea blue to bright yellow , orange , red , even white or off-white would probably work .